Electromagnetic lock



Dec. 20, 1955 A. w. HAMILTON 2,727,772

ELECTROMAGNETIC LOCK Filed Nov. 5, 1953 A/exabdar W Hamil/on INVENTOR.

- BY "fl -M United States Patent ELECTROMAGNETIC LOCK Alexander W.Hamilton, Hopewell Township, Washington County, Pa.

Application November 5, 1953, Serial No. 390,292

1 Claim. (Cl. 292-444) This invention relates to a magnetic lock andmore specifically provides a magnetic lock for use in conjunction withclosures such as car doors, bus emergency doors, house doors and windowsor the like.

An object of this invention is to provide a magnetic lock having anelectromagnetic coil surrounding a core for attracting a block orabutment of magnetic material on the door or closure.

Another object of this invention is to provide a magnetic lock whereinthe abutment or block is spring loaded will become subsequently apparentreside in the details 1 of construction and operation as more fullyhereinafter described and claimed, reference being had to theaccompanying drawings forming a part hereof, wherein like numerals referto like parts throughout, and in which:

Figure 1 is a top plan view of the magnetic lock of this invention inoperative position between a door closure and a door frame;

Figure 2 is a longitudinal, vertical section taken substantially alongthe section line 2-2 of Figure 1 showing the details of construction ofthe magnetic lock;

Figure 3 is a transverse, vertical section taken substantially alongsection line 3-3 of Figure 2 showing details of the retraction springfor the abutment block; and,

Figure 4 is an end elevation view looking at the magnetic coil.

Referring now specifically to the drawings, it will be seen that thenumeral generally designates the magnetic lock of this invention for usein retaining a closure 12 in closed relation in a closure frame 14.

The magnetic lock 10 includes a coil 16 mounted upon an end washer 18and surrounding a core 20 of magnetic material. The electric coil andwire 16 is covered with successive windings of insulating tape 22 forprotecting the coil wires making up the coil 16. The end washer 18 ismounted in the door frame 14 by suitable fastening members 24 andattaching lugs 26 which are secured to the end washer 18. A ground wire28 is used to ground the coil 16 to the door frame and an electricalsupply wire 30 is connected to an electrical source 32 through a switch34 which in this instance is mounted upon the dashboard 36 of anautomobile.

As shown in Figure 2, the metallic core 20 has a portion extendingbeyond the confines of the end washer 18 and the core 20 is welded orbrazed to the washer 18 wherein the core 20 is stationary in relation tothe coil 16.

2,727,772 Patented Dec. 20, 1955 Now referring specifically to the lefthand portion of Figure 3 it will be seen that a cylindrical member 38having an outwardly projecting flange 40 secured to the door 12 bysuitable fastening means 42 with the cylindrical portion 38 extendingthrough an aperture in a portion of the door 12 wherein the tubularportion 38 is recessed into the interior of the door 12. The cylindricalor tubular portion 38 has an inwardly extending flange 44 partiallyenclosing the end of the tubular member 38 and a screw threaded plug 46is inserted into the other end of the tubular member 38 therebyenclosing the tubular member 38 thereby forming a socket member. Anadjustment screw 48 is threadedly engageable with a threaded aperture inthe plug 46 and extends into the bottom of the tubular member 38 for apurpose described hereinafter. A bolt or rod member 50 is slidablypositioned in the tubular member 38 and is engaged by the inwardlyextending flange 44 for guiding movement thereof. A screw threadedwasher 52 is secured to the inner end of the rod 50 and closely andslidably engages the interior of the tubular member 38. The inner end ofthe rod 50 includes an indented portion 54 for engaging the adjustingscrew 48. A coil spring 56 is disposed between the flange 44 and thewasher 52 for urging the rod 58 inwardly of the tubular member 38. Anenlarged head or abutment 58 is secured to the outer end of the rod andincludes a socket or recessed portion 60 for engaging the projecting endof the core 20 when the magnetic lock is energized.

It will be understood that when the door 12 is closed and the electriccoil 16 energized, the core 20 will attract the head 58 which is ofmagnetic material thereby engaging the end of the core 20 in therecessed portion 60 and maintaining the door 12 in closed position.

From the foregoing, the construction and operation of the device will bereadily understood and further explanation is believed to beunnecessary. However, since numerous modifications and changes willreadilyoccur to those skilled in the art, it is not desired to limit theinvention to the exact construction shown and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the appended claim.

What is claimed as new is as follows:

An electromagnetic lock for securing a door in closed position in aframe, said lock including: an electromagnet mounted in the frame, saidelectromagnet comprising a winding and a fixed core projectingtherefrom, a cylinder mounted in the door and having an opening in oneend, a removable screw plug closing the other end of said cylinder, abolt mounted for longitudinal reciprocation in the cylinder in spaced,concentric relation thereto and extending slidably through the opening,said bolt being operable to projected position by the electromagnet andcomprising a socketed head on its outer end for the reception of thecore, a washer threaded on the inner end portion of the bolt andslidable in the cylinder, a coil spring encircling the bolt and engagedwith the washer for retracting said bolt, and a screw threaded foradjustment through the plug and engageable with the inner end of thebolt for limiting the movement of said bolt under the influence of thecoil spring.

References Cited in the file of this patent UNITED STATES PATENTS1,958,940 Cavanaugh et al May 15, 1934 2,219,186 Hornfeck Oct. 22, 19402,659,114 Anderson et al; Nov. 17, 1953

